a typical x-ray examination room, what is considered a secondary protective barrier?
- ANS-ceiling
Which statement correctly describes the LD 50/30?
- ANS-Lethal dose for 50% of the population in 30 days
Which
...
a typical x-ray examination room, what is considered a secondary protective barrier?
- ANS-ceiling
Which statement correctly describes the LD 50/30?
- ANS-Lethal dose for 50% of the population in 30 days
Which protective feature is designed to reduce exposure to the patient during fluoroscopic procedures?
- ANS-Foot switch.
For which long term effect is a 28-year-old radiographer with a cumulative effective dose (CumEfD) of 200 mSv (20 rem) at an increased risk?
- ANS-cancer
Which is an advantage of using a optically stimulated luminescent (OSL) dosimeter as opposed to a film badge?
- ANS-Not fogged by heat.
A portable knee exam performed in the operating room results in a beam intensity of 2.5 milligray (mgy) at 32 inches. What is the intensity of the beam if the same exposure factors are used for a post-operative knee at a distance of 40 inches?
- ANS-1.60 mgy.
The inverse square formula (I1/I2=D22/D21) is used to determine the new intensity: 2.5 / x = 1600 (40 squared) / 1024 (32 squared); x = (2.5) (1024) / 1600 = 1.6 mgy.
Which type of personnel dose monitoring devices is the best choice to monitor the whole body dosage of radiographers?
- ANS-Optically stimulated luminescent dosimeter (OSL).
Which item can be used as an indicator of the quality of the diagnostic x-ray beam?
- ANS-Kilovolts peak (kVp).
If a radiographer receives an exposure of 0.05 millisievert (msv) at a distance of 1.5 feet from the tube of a portable x-ray unit, what will the exposure be at a distance of 6 feet from the tube?
- ANS-0.003 msv
inverse square law
In an x-ray tube, what is the the source of electrons used to make x-rays?
- ANS-Filament
When the frequency of the voltage waveform supplied to the x-ray tube is increased, what aspect is reduced?
- ANS-Heat loading on the anode disk.
Average wavelength of the x-ray beam.
Patient exposure.
The majority of x-rays in the useful beam are created as a result of which process? - ANS-Fast-moving electrons approach the nucleus ofthe target atom and slow down.
What is the dose area product (DAP) if the collimated field is 10 X 10 cm with a dose of 2 milligray (mgy)/minute? - ANS-200 mgy per cm squared.
the volume of tissue radiated (100 cm2) is multiplied by the dose received (2 mgy/min). The correct answer is 200 R per cm squared.
What is the impact of using 2.5 millimeters of aluminum equivalent filtration on the primary x-ray beam? - ANS-Reduction of the patient's skin dose.
Which condition must be met before diagnostically useful characteristic x-rays can be produced? - ANS-An inner shell electron must be completely removed.
Which change causes a decrease in resistance and an increase in current flow? - ANS-Increasing the diameter of the conductor.
The highest potential dose to the radiographer during c-arm fluoroscopy originates from which source? - ANS-The side where x-rays enter the patient.
For the protection of the radiographer, how long must the exposure cord be on a mobile radiographic unit? - ANS-2 meters
The annual effective dose equivalent limit for infrequent exposures recommended by the National Council on Radiation Protection (NCRP) for a member of the general public is equal to how many millisievert (msv)? - ANS-5
Which term refers to the radiation that exits the x-ray tube through the collimator? - ANS-Primary.
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